An analog to digital converter (ADC) is an electronic device that converts an input analog voltage or current to a digital value indicting the magnitude of the voltage or current. An ADC has a resolution indicating the number of discrete values it can produce over a range of analog values. ADCs are useful, for example, in electricity metering applications. Electricity meters can measure the amount of power consumed by a consumer on an electric utility grid.
ADCs in electricity meters and other applications sometimes operate in environments that are electrically and physically harsh. For example, high temperature swings, lightning strikes, high voltage power surges, and indirect nearby high current surges can damage an ADC. To test an ADC to ensure that it is still operating properly, the ADC can be taken off-line. In electricity metering applications, taking the electricity meter off-line can prevent revenue billing.